Assessment of effect of ductile tearing on cleavage failure probability in ductile to brittle transition region
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The fracture behaviour of ferritic and ferritic martensitic steels in ductile to brittle transition (DBT) region has been extensively studied in recent years and a probabilistic approach of master curve method is generally used to describe the fracture toughness of BCC steels in DBT region as a function of temperature. The assessment of cleavage failure probability however is still untouched in the upper region of ductile to brittle transition, although various extensions of master curve approach and various local approaches has been explored. Additionally the geometry and loading in tension and bending also adds up to the difficulties when cleavage failure is assisted with prior ductile tearing. In this work the cleavage fracture is investigated in upper region of DBT and a modified master curve approach is presented which can satisfactorily describe the fracture toughness as a function of temperature as well as amount of ductile tearing preceded by cleavage.
KeywordsDuctile tearing Upper DBT Master curve Triaxiality
The authors would like to express their gratitude to Dr. Kim Wallin for the method of master curve and his extensive work on the subject which has inspired our previous work as well as this work. We would also like to acknowledge the pioneer work of Dr. B. Z. Margolin from which many improvements were made in the basic conceptualization of this work. The authors would also like to express their gratitude to Mr. Avinash Gopalan for the technical discussion which guided this work in the present direction. The authors would also like to express gratitude to the scientific community who made the Euro fracture data available for our analyses in open forum. The authors extend their gratitude toward the institutional authorities of Bhabha Atomic Research Centre, Mumbai for experimental facilities.
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